Insurgents have killed 15 Iraqi soldiers travelling in a convoy south of Baghdad, police and officials say.

The attack happened near the town of Latifiya, in a lawless area known as the "triangle of death".

The violence came on the second anniversary of the fall of Baghdad to the US-led coalition.

Tens of thousands of Iraqis joined an anti-US protest in Firdus Square, where Saddam Hussein's statue was toppled on 9 April 2003 as millions watched on TV.

Chanting "No to America" and "No to the occupiers", they pulled down and burned effigies of Saddam Hussein, US President George W Bush and British Prime Minister Tony Blair.

Details of the attack near Latifiya are still sketchy, with conflicting accounts of how the soldiers died.

Police in the nearby town of Mahmudiya told Reuters news agency that gunmen forced the soldiers' truck to stop before shooting and killing them.

However, an Iraqi defence ministry official told AFP news agency that they were blown up by a roadside bomb.

Pullout urged

News of the attack came as protesters poured into Firdus Square for a rally called by radical Shia cleric Moqtada Sadr.

They joined a group who had been in the square since Friday night.

Many of the demonstrators had travelled hundreds of miles from Shia cities in southern Iraq to attend the rally. Others came from Baghdad's Sadr City slum, scene of a failed uprising by Mr Sadr's Mehdi Army fighters last year.

TWO YEARS ON

More than 130,000 US troops remain in Iraq

Unofficial estimates of civilian deaths range from at least 15,000 to almost 100,000